Making Males

Virtually all of the flowers are male. Only a few female flowers can be seen.

THERE IS ONLY ONE REASON I can think of that someone would want to force a female plant to develop male flowers: to use the pollen from these flowers to create all-female seed, often called feminized seed. This seed can be used to produce an all-female garden without having to pull males.

Mammals and most other higher animals grow one set of reproductive organs in their lives, so their sex is set. However, if given hormones from the other sex, their secondary sexual characteristics will be affected. Females will lose breast size and develop more body hair and a deeper voice, while males will develop more body fat, develop a higher pitched voice and lose body hair.

Flowers are plants’ reproductive organs. Unlike mammals, plants develop new reproductive organs, flowers, repeatedly, so the sex of their organs is not set in the same way as mammals. Sex hormones, or chemicals that affect the sexuality of the plant, have a profound effect on the developing flowers. Given a male-simulating/stimulating chemical, the plants grow male flowers on female plants. This happens not only with cannabis but also with cucurbits such as cucumbers and melons, some of which have been bred to grow all-female plants. Inducing male flowers is commonly used to create pollen to fertilize female flowers of greenhouse-grown English cucumbers.

Four female Purple Kush plants. Notice that the two sprayed plants had male flowers while the controls, which were not sprayed, produced normal female flowers.

Cannabis has unusual sexuality. It is the only annual plant I know of that is dioecious, that is, it has separate male and female plants. Other annuals produce both male and female reproductive organs either on the same flower, such as tomatoes, or on separate flowers, such as squash and other cucurbits. Plants that have a single sex make it easy for gardeners to cross or breed cannabis. Just separate the males from the females so that only the pollen from the male(s) that you want to use gets to the female(s) you want to bear seeds.

A naturally male cannabis plant, just as a male mammal, carries both male and female genes, while female plants carry only female genes. Because the male delivers only one set, to be matched with one set from the female, the resulting seed will become either male or female.

Induced male flowers on female plants are not quite the same as flowers on naturally occurring males. Although chemicals induce or force male flowers on the female plants, they do not change the plant’s DNA. The pollen has only female genes since female plants have two sets of female genes, thus all the plants produced from the pollen will be female.

Either you can gather the pollen and then “paint” the female flowers with it using a small watercolor or cosmetic brush, or you can place a male and females in the same room, use a fan to circulate the air, then the pollen is airborne and will soon be captured by the stigmas of the female plants. The white, creamy, or pinkish stigmas are hollow tubes with small brushes that filter the air. As soon as appropriate pollen touches one of the brushes it is drawn into the tube and the sperm is transported down to the waiting egg at the base of the flower. The flower is pollinated and the seed begins to grow.

The bud of this sprayed Sour Diesel is producing copious numbers of male flowers.

There is a caveat here. If this technique is used generation after generation you will probably be selecting inadvertently for hermaphroditism, which is an unfavorable trait. (Natural hermaphrodites are dangerous pollinators and should be removed from the garden and destroyed.) Plants with a more hermaphroditic tendency are more likely to be more robust pollen producers. For this reason this technique should be used only for the retail or grow-out generation of seed, so that the tendency for hermaphroditism does not get concentrated over several generations.

Techniques to Induce Male Flowers

The first method marijuana growers used to induce male flowers in female plants was the use of silver nitrate. This is a messy substance to use and can temporarily stain your skin grey, which is great for zombie parties but… Then researchers developed a more potent malinator, silver thiosulfate. It is made by combining silver nitrate and sodium thiosulfate. This is a great chemistry project but may be a little detailed and tedious for most readers. Another problem is that both silver nitrate and sodium thiosulfate are on restricted chemicals lists and are only delivered to certain addresses and laboratories.

The unsprayed control, a Sour Diesel that matched the sprayed plant, produced only female flowers.

Colloidal silver is a safe consumer product that is available at health food stores and on the Internet. It is produced by running an electrical current through water using a piece of silver as the anion electrode, the electrode that sends the current out. Some of the silver jumps into the water and develops a stable solution.

My family members use colloidal silver when they feel a cold or other infectious attack imminent. It is a clear liquid, has no taste, is easy to use, and needs no special instructions. It is not poisonous and it is taken internally for health reasons by drinking it.

Colloidal silver can also be used to induce male flowers in female plants. Since it is safe to use, has no legal restrictions, is easy to obtain, and is quite inexpensive, it is the malinator of choice.

How to Do It

The method I used to induce the development of all-female pollen from female plants was to spray the plants with 120ppm colloidal silver three times, three to four days apart, at the same time as the plants were placed into the flowering regimen of 12 hours of light and 12 hours of uninterrupted darkness. The leaves were sprayed until dripping each time.

Spray bottle with 120ppm silver colloidal spray. It was used to spray the plants three times over a one-week period when the light regimen was changed to flowering.

A grower whom I recently met used a slightly different technique. He sprayed 30ppm colloidal silver daily for two weeks at the change of regimen and observed the same results.

The results: 40 days after their first exposure to colloidal silver the three plants that I sprayed all had robust production of male flowers with ample pollen production. Two of the plants were rooted clones and one of the plants had been growing vegetatively for several weeks before being sprayed. Matching plants of the same varieties were used as controls. The controls produced only normal female flowers.

Using colloidal silver to induce male flowers makes it safe, easy, and inexpensive to produce your own feminized seeds.